Antifungus wrapper and method of pest control



Patented Aug. 23, 1949 PEST CONTROL Lawrence H. Flett, Scandale, N. Y.,assignor to Allied Chemical & Dye Corporation, New York, N. .Y., acorporation of New York No Drawing. Application March 27,1947.

- Serial No. 737,707

22 Claims. 1

This invention relates to new pest control agents for control ofiungiand other organisms and more especially to agents for prevention and-control of mold and mildew on foodstuffs such as bread and cheese andother perishable organic material.

As is well known, many organic materials which enter, into commerce aresubject to attack by fungi and other organisms. For example foodproducts such as cheese, bread, fruit and vegetalakes are subject torapid attack and growth of mold and mildew thereon, which adverselyaffects the quality, taste and marketability of the product, andtextilesand other articles of apparel, such as cotton piece goods,sheets, woolens,

leather goods and the like frequently become mil-.

dewed. Seeds are also highly susceptible to attack by many fungous andbacterial diseases. In fact, substantially any material derived fromplants may be subject to attack by mildew, mold or other fungi, or otherorganisms.

In view of the above there is a great demand for compounds which willeffectively protect organic material of the type described from fungousdiseases. Many of the compounds suggested for .use in this connection,e. g. mercury compounds.

are toxic, so that use thereof, particularly inconjunction withfoodstuffs, is highly disadvantage- I ous. Other compounds suggested foruse have the disadvantage of imparting objectionable odor or taste tothe materials they are designed to preserve. Accordingly, theaforementioned demand remains unsatisfied.

It is an object of this invention to provide new agents for control offungi and other organisms, which are especially suited for use inpreserving contact with the material; or the organic mate-" rial may beexposed to hot gases containing vapors of one of the above esters in asuitable enclosure; The esters may also be employed for control of fungion organic material infested therewith by application to the host in anyconvention-al manner, as in the form of a dust, solution or dispersion.

my invention, wrapping material such as pap waxed paper or cellophane,is impregnated or coated with a composition containing one or more ofthe above esters to produce a wrapper from which the antlmycotic agentslowly vaporizes over a prolonged period of time and which is highlysuitable for wrapping bread, cheese and other foodstufl's subject tomold attack; the antimycotlc agent of this invention not only protectsthe foodstuff from mold, but when present in amounts of 5% or less byweight or the wrapping material, imparts no objectionable odor or tasteto the food product.

The esters employed in accordance with my invent-ion are the dialkylesters of a, fi-dichlorosuccinic acid in which the alkyl groups eachcontain not more than 4 carbon atoms. The preferred products employed inaccordance with my invention are the lower dialkyl esters of a,p-dichlorosuccinic acid, e. g. dimethyl, diethyl, or methyl ethyldichlorosuccinate. Use of the dimethyl or diethyl esters, asdistinguished from the propyl or butyl esters, is preferred because oftheir higher volatility, but I have found the propyl and butyl esters tobe useful if maintenance of an antimycotic atmosphere over a long periodof time is desired; Mixtures of two or more of the above esters may alsobe employed. As is known, the above esters form stereoisomers; inaccordance with the invention, mixtures of the stereoisomers aregenerally used, but, if desired, the individual isomers may be employed.

The esters described slowly vaporize at room temperature (about 25 C.)so that they may be employed as antimycotic agents in accordance withthis invention by placing the organic material to be protected incontact with, or closely adjacent to, the esters at room temperature,for example by enclosing the material in a wrapper coated or impregnatedwith one or more of the esters. However, the above esters may also beemployed in accordance with my invention in any manner in whichfumigants are customarily utilized, e. g. by exposing the organicmaterial to be protected to vapors of the esters in a suitable chamberby introduction of air at room temperature or higher saturated with theesters, or

by permitting asuitable amount of the esters or solutions thereof tovaporize within a closed space, whereby the organic material isthoroughly impregnated with vapors of the ester and thereby protectedagainst attack by fungi for a prolonged period of time.

In accordance with the preferred embodiment In accordance with apreferred embodiment of of my invention, wrapping material to be usedwrapped materials for wrapping organic material-such as food ,stufls,textiles and the like subject to fungus attack, is. impregnated orcoated with a'composition containing one of the above described estersor a mixturefthereoi, preferably a lowerdialkyl dichlorosuccinate, Thewrapping material treated may be any suitable wrapper such, for example,as the'various paperwrappers, wa ed or other moisture-resistant paper,glassine, cellophane,' -'Piiofllin (a rubber hydrochloride film),tinfoil or anyother conventional wrapper. The ester may be applied tothe wrapper in various ways;

- in combination for example, by spraying a solution of the ester inether or othervolatile solvent thereon and permitting the solvent toevaporate, or by dipping the wrapper in a solution of the ester andevaporating thesolvent. A particularly advan- U tageous method ofapplying the ester to the wrapper involves incorporating one of theesters or a mixture thereof in material to be used for coating thewrapper to render it moistureor greaseproof and/or heat-sealing;for-example, a small percent of a lowerdialkyl dichlorosuccinate may ibe admixed with paramn .or other wax compositions used for coating paperor cellophane to render them moisture-resistant and heat-seal- H p pwith the usual spray supplements or with suitable: wetting, emulsifying,

sticking and spreading agents. They may also be used in combination withinsecticides or other fungicides, if desired. When utilized in themanner above described, the composition applied to the fungushost'preferably should not contain more 20%, by weight, of the esters orthis invention, in order toavoid injury to the plant or other host.

' Thefollowing examples are illustrative of my invention: p p

Example 1.--A solution of dimethyl dichlorosuccinate inether was sprayedon a cellophane" sheet and the ether evaporated to produce a sheetcontaining 2%, by weight, or the succinate. A boxof fresh raspberrieswas wrapped in this sheet andthe wrapped box then exposed to normalatmospheric conditions; for purposes of com parison another box of freshraspberries was wrapped with untreated cellophane and exposed to thesame conditions. The box wrapped I with the untreated sheet developedmold'within three days, whereas the box wrapped with the treated sheetdeveloped no mold even after 20 days exposure.

ing. Since the esters used'in. accordance with 8 this inventionhaverelatively high/boiling points (238 C. or higher), they maybeincorporated in coatings to be applied by the so-called hot melt?technique as well as in coatings to beapplied in solution. The amount oithe ester incorporated with the wrapping material in accordance withthis embodiment of my invention may vary but preferably should not beover 5% by weight of the wrapper, and may desirably a comprise from 0.5%to 1% upto 2%, by weight thereof in cases wherein the ester isincorporated in a moisture-resistant coating on the wrap-i. per, theamount of ester may desirably vary from 1% to 2%, by weight, of thesolids in the coating,

Use of larger amounts thanahove specified will be indicated in instanceswhere it is desired to, de-

stroy all possible organismae. g. in the wrapping of fabrics. In thosecases, howeven'where selective killing action is desired, such as in thewrapping of seedswhere it is desired to kill seed borne diseases withoutkilling the seed germ, use of such larger amounts may be disadvanatageous, since it has beenfound that the abovedescribed esters in. pureform are highly d8 animal, and if used at too high concentrationsExample 2.'Asol'ution of dimethyl dichlorosuccinate mother was sprayedon a cellophane sheetand the ether evaporated to produce a sheetcontaining 1.8% byweight, of the succinate. A loaf of bread was thenwrapped in this sheet and the wrapped bread exposed to normalatmospheric conditions; for the purpose of comparison a like loaf ofbread was wrapped with untreated cellophane and exposed to the sameconditions. The bread. wrapped in the untreated sheet developed moldwithin three days, whereas the the wrapped bread was exposed to normalat- ,mosphericconditions; for. purposes of comparison alike loaf ofbreadwas wrapped with an untreated paper wrapper and exposed to theYstructive to. all forms of life, both plant and may'adversely afiecttheorganic materials which they are designed to protect. Wrappersimpregnated or coated with compositions containing one or more oftheestersas above described give off vapors of the ester over aprolonged period or time, so that they may be used to wrap foodstuffssuch as bread, cheese, fruit andthe like or other organic materialsubject to attack A The cheese wrapped in theuntreated paper del by moldor mildew in order to Drotectthem'from suchattack; use or such wrappers,Ihaveiound,

does not impart undesirable odoror taste to the The esters abovedescribed also be em ployed to control fungi by'application to thefungushost of compositions containing one or i more of the aboveesters'in combination with a suitable carrier, which may or may not.have above estersmay be. applied in the form or a solution orsuspension, or as a dust admixed with a a suitable dust carrier such astalc. pyrophyllite, I :clayor the like the above esters may be appliedwrapped in theuntreated paper quickly develsameconditions'. The. breadwrapped in treated paper had developed no' mold even after ten daysexposure. e

Example 4.--Apaper wrapper was dipped in an alcohol solution of dimethyldichlorosuccinate and the alcoholevaporated to produce a sheetcontaining "5%, by weight, of the succinate. Cheese was wrapped intthiswrapper and the wrapped cheese was exposed to normal atmosphericconditions; for purposes of comparison a like cheese was wrapped with anuntreated paper 3 wrapper andexposed to the same conditions.

veloped mold after. 5 days, whereas the cheese wrapped in treated paperhad develo'pednomold even after ten days exposure.

"Example 5.--A cellophane sheet was coated with a mixture of paraflinwax and dimethyl dichlorosuccinate to produce a coated sheet con- Cream'cheese was then wrapped in the coated sheet and taining2% by weight ofthe succinate.

exposed to normal atmospheric conditions; for purposes of comparisoncream cheese was also wrapped in a cellophane wrapnercoated withparaflin wax containing none of the succinate, and exposed to the sameconditions. The cheese oped a strong yeasty taste andiin less than amonth showed a serious mildew condition. The cheese wrapped in thetreated paper, however, was kept for six months without growth ofmildew; in addition, the presence of the succinate in the wrapper .couldnotbe detected in the taste of the cheese, which remained fresh throughthe period.

Example 6.A bread wrapper was prepared by coating cellophane with amixture of paraflin wax and dimethyl dichlorosuccinate so as to producea coated wrapper containing 1%, by weight, of the succinate. Freshlybaked bread was then wrapped in thi wrapper and exposed to normalatmospheric conditions; for purposes of comparison a similar loaf ofbread was wrapped with the same typeof wrapper coated with paramn waxcontaining none of the succinate and ex.-

I in an ether solution containing dimethyl dichlorosuccinate, mineraloil and paraffin wax and the wrappers permitted to dry for five minutesto evaporate the ether; solutions were chosen so that four test paperswere obtained, each containing 392% -by weight paraflln wax, 392% byweight mineral oil and .04.9%, .098%, .196% and 392% by weight,respectively, of the succinate. Each of the four test papers was thenused as individual wraps for tomatoes, six tomatoes being employed ineach test; after wrapping, the tomatoes were exposed to normalatmospheric conditions. For purposes of comparison six tomatoes werealso wrapped in untreated fruit wrappers. After four days one of the sixtomatoes wrapped in the untreated paper was found to be moldy, and after14 days an additional tomato wrapped in untreated paper was soft andmoldy; by contrast, at the end of 14 days all the tomatoes wrapped withthe treated paper were still sound.

Example 8.-A Pliofilm sheet and waxed paper were impregnated with asolution of dimethyl dichlorosuccinate in a petroleum ether so as toproduce sheets containing 1%, by weight, of the succinate; Each of thesesheets was then placed under the cover of a Petri dish containing apotato-dextrose-agar medium which had beenseeded with spores of anAspergillus species of fungus, the dishes being of a size such thatthere was a distance of 15 to 1'7 mm. between the impregnated sheet andthe surface of the culture medium; for purposes of comparison a similarculture was grown in a Petri dish in which no treated sheet wasinserted. After three days in from fungus infestation which comprisescontacting said material with-vapors of a diaikyl ester ofafi-diChlOl'OSllCOllliC acidin which the alkyl groups each containnotmore than 4 carbon atoms. 7 i

3. A method of protecting foodstuffs from fun gus infestation whichcomprises'contacting the 4. A method of protecting organic material fromfungus infestation which coniprises'enclosing the organic material in awrapper having incorporated therewith not more than 5%, by

weight, of a dialkvl ester of cfi-dichlorosuccinic acid in whichthealkyl groups each contain not cubationthe control sample haddeveloped a substantial growth of fungus, whereas-there was no growth offungus in the dishes in which the treated sheets had been placed.

Since certain changes may be made in the above process and in thearticles above described without departing from the scope of theinvention, it is intended that all matter contained in the abovedescription shall beiinterpreted as illustrative and not in a limitingsense.

I claim;

1. A method of pest control which comprises subjecting organic materialsubject to infestation to the action of a'dialkyl ester oftap-dichlorosuccinic acid in which the alkyl groups each contain notmore than 4 carbon atoms.

2. A method of protecting organic material more than 4 carbon atoms,said ester slowly vaporizingand exerting an antimycotic action over aprolonged period of time.

5. A method of protecting organic material from fungus infestation whichcomprises contacting said organic material with vapors of a lowerdiaikyl ester of a,fl-dichlorosuccinic acid.

6. A method of protecting organic material from fungus infestation whichcomprises enclosing said organic material in a wrapper havingincorporated therewith not more than 5%, by -weight,'of a lower dialkylester of mil-dichlorosuccinic acid, said ester slowly vaporizing andexerting an antimycotic action over a prolonged period of time.

'7. A method of protecting organic material from fungus infestationwhich comprises enclos ing said organic material in a wrapper havingincorporated therewith not more than 5%, by weight, of the dimethylester of a,fl,-dichlorosuccinic acid, said ester slowly vaporizing andexerting an antimycotic action over a prolonged period of time.

8.. A method of preserving cheese foodstuffs which comprises enclosingthe foodstuff in a wrapper having a small percent of dimethyldichlorosuccinate incorporated therewith as an effective high boilingantimycotic agent.

9. A method f protecting foodstuffs from rungus infestation whichcomprises enclosing the foodstuff in a wrapper having incorporatedtherewith not more than 5%, by weight, of the dimethyl'ester ofa,p-dichlorosuccinic acid. the ester slowly vaporizing and exerting'anantimycotic action over a-prolonged period of time.

10. A protective wrapper made of wrapping material having incorporatedtherewith as an ef-- 12. An anti-fungus wrapper made of wrappingmaterial having incorporated therewith as an effective, high boilingantimycotic agent a small percent of the dimethyl ester ofa,B-dichlorosuc-' 7o cinic acid, said ester slowly vaporizing over aprolonged period of time.

13. An anti-fungus wrapper made of moistureresistant coated paper,having as an effective high boiling anti-mycotic agent a small percentof a lower diaikyl dichloro succinate incorporated in ingantimycoticagent. r

izing over a proiongedi periodof time.

14. An antifungus wrapper made 015 moistiw,

resistant'coated paper, coated with a heat-scale ing coatingcomposition, saiii eomposition'havinsw as anefie'ctivenigh boilinganti-meiotic Mimi: .a s nall'peroent of a lowerlidialky l momma ,81163'oinate incorporated in the coating, anti-X mycotic agent slowlyvaporizing rover aiprolonzed period of time. i

15. anti-fungus wrapper made of resistant coatedpaper, havinzaboutito 2%of a lower dialkyl dichloro' snocinate incorporated "in the coating.

v '16. An-=anti-funsuswrapp rmmadeioimoisture-1 resistant coated paper,havingabout 1 to2% oi -dimethy1 diohloro succinate incorporated in thecoating.

. 17. Alproteotive wrapperzmade' oi wrappingi; I:

material'coated with a coating containing a small percent of'a, lowerdialkyl ester of p diohlorosuccinic aciq as an efl'eotive'high boilinganti-r; mycotic agent, said ester vaporizing over a prolonged period :oftime.

18. An anti-iungusjwrapper mine-m: sheet wrappingimaterial coated with amoisturerrer i the coatinasaidhnti-niyootio agentslowiy vim-jofoheotwropp l material coated with a'moishire-resistant wax-containing"coating, composition, said eompooitionhavinz a small percent or a 60mmthereinaaan eflectivehish boiling gnumycotic agent. i i

sistant (floating composition, said wrapperflhavinr a smaiiperoent ofdimethyl dichloro'suoeinatew I aneiiectivehigh boil x incorporatedtherewith as 4 21:' An anti-411mm mapper made or wrappingmaterialhavingincorporated therewith as an eifective,hignboilingantimyeotioagent not more than 5%, byweizht; oi' tiiinetlwidichloro succinate. a

2. An anti-ionsuanxrapper made oi moiatureresistant coated sheetwrappingmateriaihaving dimethyl diohlorosuceinate incorporated "in thecoating as an eii'edtive, high boiiing a'ntimyctic 'ag'ehtJthe amount ordimetnyl diei ioro succinata morer than 5%. byweighiaoi thei wrap iiipreierenoesoitecivf

